Bottom Line:
We present our technique and review the results from a cohort of patients who underwent minimally invasive lumbar pedicle screw placement utilizing the O-arm imaging unit in conjunction with the StealthStation Treon System.All breaches were graded as 0-2 mm and were asymptomatic.In the remaining three patients, post-instrumentation O-arm imaging did not demonstrate pedicle screw misplacement.

Background: Pedicle screw misplacement is relatively common, with reported rates ranging up to 42%. Although computer-assisted image guidance (CaIG) has been shown to improve accuracy in open spinal surgery, its use in minimally invasive procedures has not been as well evaluated. We present our technique and review the results from a cohort of patients who underwent minimally invasive lumbar pedicle screw placement utilizing the O-arm imaging unit in conjunction with the StealthStation Treon System.

Results: A total of 52 screws were placed. Forty screws were inserted in eight patients who had postoperative CT, and a misplacement rate of 7.5% was noted including one lateral and two medial breaches. All breaches were graded as 0-2 mm and were asymptomatic. In the remaining three patients, post-instrumentation O-arm imaging did not demonstrate pedicle screw misplacement.

Conclusion: Although this initial study evaluates a relatively small number of patients, minimally invasive pedicle screw fixation utilizing the O-arm and StealthStation for CaIG appears to be safe and accurate.

Figure 0001: Typical patient positioning with the O-arm in the “parked” position

Mentions:
Each patient was positioned prone on a radiolucent Jackson frame with the StealthStation camera placed at the foot. The O-arm was then positioned so that the target spinal segment was centered in the field of view. To accomplish this, anterior-posterior (A/P) and lateral views were obtained in 2-D fluoroscopy mode. The O-arm was then moved toward the patient’s head to the “parked” position, which allowed access to the patient for the surgical procedure [Figure 1]. After standard skin sterilization and draping, the O-arm was re-positioned so that the target spinal segment was centered within the O-arm ring. A stab incision was made over the posterior iliac crest and a percutaneous iliac pin was placed. The StealthStation reference arc was then attached to the iliac pin. At this point, the O-arm in 3-D multi-planar mode was used to obtain a CT-type image of the spine. The O-arm then transferred the image data to the StealthStation for auto-registration and production of multiplanar images that included trajectory viewpoints. At this point, image guidance was ready for use. Of note, no surgeon-derived registration of the spine to the StealthStation 3-D image was necessary.

Figure 0001: Typical patient positioning with the O-arm in the “parked” position

Mentions:
Each patient was positioned prone on a radiolucent Jackson frame with the StealthStation camera placed at the foot. The O-arm was then positioned so that the target spinal segment was centered in the field of view. To accomplish this, anterior-posterior (A/P) and lateral views were obtained in 2-D fluoroscopy mode. The O-arm was then moved toward the patient’s head to the “parked” position, which allowed access to the patient for the surgical procedure [Figure 1]. After standard skin sterilization and draping, the O-arm was re-positioned so that the target spinal segment was centered within the O-arm ring. A stab incision was made over the posterior iliac crest and a percutaneous iliac pin was placed. The StealthStation reference arc was then attached to the iliac pin. At this point, the O-arm in 3-D multi-planar mode was used to obtain a CT-type image of the spine. The O-arm then transferred the image data to the StealthStation for auto-registration and production of multiplanar images that included trajectory viewpoints. At this point, image guidance was ready for use. Of note, no surgeon-derived registration of the spine to the StealthStation 3-D image was necessary.

Bottom Line:
We present our technique and review the results from a cohort of patients who underwent minimally invasive lumbar pedicle screw placement utilizing the O-arm imaging unit in conjunction with the StealthStation Treon System.All breaches were graded as 0-2 mm and were asymptomatic.In the remaining three patients, post-instrumentation O-arm imaging did not demonstrate pedicle screw misplacement.

Background: Pedicle screw misplacement is relatively common, with reported rates ranging up to 42%. Although computer-assisted image guidance (CaIG) has been shown to improve accuracy in open spinal surgery, its use in minimally invasive procedures has not been as well evaluated. We present our technique and review the results from a cohort of patients who underwent minimally invasive lumbar pedicle screw placement utilizing the O-arm imaging unit in conjunction with the StealthStation Treon System.

Results: A total of 52 screws were placed. Forty screws were inserted in eight patients who had postoperative CT, and a misplacement rate of 7.5% was noted including one lateral and two medial breaches. All breaches were graded as 0-2 mm and were asymptomatic. In the remaining three patients, post-instrumentation O-arm imaging did not demonstrate pedicle screw misplacement.

Conclusion: Although this initial study evaluates a relatively small number of patients, minimally invasive pedicle screw fixation utilizing the O-arm and StealthStation for CaIG appears to be safe and accurate.